JP3642320B2 - Plating method and apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a plating method and apparatus, for example, a plating method and apparatus for printed wiring boards and the like used in various electronic devices.
[0002]
[Prior art]
As an example of an object to be plated, a printed wiring board used for assembling various electronic devices has a through-hole with a hole diameter of 0.3 mm or more. With the progress of weight reduction and high density, printed wiring boards having non-through holes with a hole diameter of 0.3 mm or less and an opening diameter of 0.1 mm or less have been used.
[0003]
In these printed wiring board manufacturing methods, there are many chemical treatments in which the object to be plated is placed in a basket provided with a crosspiece in the processing steps for forming a circuit conductor. Here, the plating process will be described.
[0004]
First, a plating treatment basket in which an object to be plated provided with through holes and non-through holes is inserted is immersed in a plating tank filled with a plating solution. In the object to be plated having a hole, the plating solution is infiltrated into the hole of the object to be plated at the time of immersion, but as is clear from the comparison between FIG. 2 (a) and FIG. The smaller the liquid is, the more difficult it is for the liquid to enter the hole 12, and the bubbles 13 stay in the hole 12. Further, in FIG. 2C, since the hole 12 is small and is not a through-hole, the bubble 13 tends to stay. In order to release the accumulated bubbles 13, the plating basket is swung in the horizontal direction to release the bubbles 13 in the holes 12.
[0005]
Next, in the plating process, as shown in FIG. 3, a metal to be plated is deposited on the surface of the object 11 and a reaction gas 14 such as hydrogen is generated by a chemical reaction. The reaction gas 14 is attached to the object 11 by the attractive force of the object 11. Here, unless the reaction gas 14 generated in this plating process is promptly separated from the object 11 to be plated, the reaction gas 14 hinders metal deposition due to plating, so that plating is not deposited or plating thickness is insufficient. In particular, as shown in FIG. 3B, when the hole diameter of the hole 12 is smaller than that of FIG. 3A or when it is a non-through hole as shown in FIG. 3C, the flow of the plating solution tends to deteriorate.
[0006]
In order to detach this reaction gas 14 from the object 11 to be plated, as shown in JP-A-62-154797 and JP-A-62-154798, a vibration generator is conventionally provided in the plating tank, A method has been adopted in which the reaction gas 14 is detached by applying vibration to the object to be plated with an amplitude in the range of 1.0 to 1.8 mm by the vibration generator.
[0007]
[Problems to be solved by the invention]
Nowadays, the printed wiring board as the object to be plated 11 has a non-through hole and a small diameter through hole with a hole diameter of 0.3 mm or less as described above, as shown in FIGS. 3 (b) and 3 (c). The flow of the plating solution is further deteriorated in the non-through holes and in the small diameter through holes having a hole diameter of 0.3 mm or less. For this reason, the reaction gas 14 is less likely to be detached from the object to be plated 11. Therefore, in the conventional method of detachment by vibration, there is a limit to detachment of the reaction gas 14 and it has become difficult to detach the reaction gas 14 sufficiently. In particular, since the non-through holes flow only in one direction as shown in FIGS. 2C and 3C, it is difficult to remove the bubbles 13 retained during the immersion, and the bubbles 13 are detached from the holes. It was extremely difficult.
[0008]
Finally, since the bubbles 13 or the reaction gas 14 at the time of intrusion cannot be separated and stay in the hole and hinder the plating, plating with a sufficient thickness inside the small-diameter through hole or non-through hole is performed. Had the problem of being unable to.
[0009]
Therefore, the present invention solves the above-mentioned conventional problems, and plating capable of performing plating with a sufficient thickness inside the non-through hole and the small-diameter through hole provided on the plating surface of the object to be plated. The object is to provide a processing method and apparatus.
[0010]
[Means for Solving the Problems]
In order to achieve this object, the present invention immerses a plating treatment basket in which an object to be plated having a non-through hole and a through hole having a hole diameter of 0.3 mm or less is fixed in a plating tank filled with a plating solution. A plating method characterized by repeatedly performing the operation of impacting the object to be plated by lifting the plating basket in the liquid in the horizontal direction while swinging it horizontally and dropping it vertically in the vertical direction; By repeating the operation of giving a shock in the vertical direction while swinging the plating treatment basket in the horizontal direction, the reaction gas staying in the small-diameter through hole or non-through hole of the object to be plated is This makes it possible to detach more efficiently, and is particularly effective for a small-diameter through-hole portion of 0.3 mm or less where it is difficult to detach the reaction gas staying in the hole.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
(Embodiment 1)
Hereinafter, the first embodiment of the present invention will be described with reference to the drawings.
[0021]
FIG. 1 is a perspective view of a plating apparatus according to Embodiment 1 of the present invention.
[0022]
First, an object to be plated 1 such as a printed wiring board having a non-through hole and a small-diameter through hole having a hole diameter of 0.3 mm or less is inserted into a treatment basket 2 and placed in a plating tank 3 filled with a plating solution as shown in FIG. Plating is performed while immersing the treatment basket 2. At this time, the processing basket 2 immersed in the plating tank 3 is provided with, for example, a fixing bar 4 as a means for fixing the object 1 to be plated, and the object 1 to be plated is fixed using the fixing bar 4. Further, an air cylinder 5 is provided above the processing car 2 as a mechanism for giving an impact to the processing car 2. This configuration is a feature of the present embodiment.
[0023]
The treatment basket 2 immersed in the plating tank 3 is first installed so as to be in contact with the basket receiver 6 provided outside the plating tank 3, and first, bubbles accumulated in the holes of the object 1 to be plated are immersed. Swing horizontally to disengage. Here, during the plating process while swinging, a reactive gas such as hydrogen is generated along with the deposition of the metal to be plated by a chemical reaction. This reaction gas adheres to the workpiece 1 due to the attractive force of the workpiece 1. Here, in order to detach the reaction gas, the processing basket 2 in the plating tank 3 is once lifted upward by a height of 10 to 20 mm from the basket receiver 6 by the air cylinder 5 and then vertically moved onto the basket receiver 6. Free fall in the direction. Due to this free fall, an impact is applied to the workpiece 1 inserted into the treatment basket 2. This movement is repeated in a cycle of 5 to 10 seconds. At the time of the impact, the value of the kinetic energy applied to the object to be plated 1 is equal to the value obtained by converting the positional energy corresponding to the height lifted by the air cylinder 5, and is proportional to the height lifted upward.
[0024]
In the present invention, when the height lifted upward is 15 mm, the vertical amplitude of the conventional vibration is 1.0 to 1.8 mm, so the amount of energy applied at the time of impact of the present invention is 8 to 15 times that of the conventional case. The reaction gas staying in the non-through hole or the small-diameter through hole of the workpiece 1 that has been difficult to remove due to the impact can be efficiently separated.
[0025]
As a result, the reaction gas staying in the non-through hole and the small-diameter through hole of the workpiece 1 that has been difficult to detach from the reaction gas is released from the workpiece 1 so that the non-through hole and the small-diameter through hole are also removed. It is possible to perform plating with a sufficient thickness.
[0026]
In addition, when the vertical movement height is less than 10 mm, the energy generated by the impact is insufficient, so that it is not possible to give a sufficient impact to the workpiece 1. Since the time required for each movement increases, the efficiency of removing the reaction gas deteriorates, and the height of the plating tank 3 and the plating solution must be increased in accordance with the height of the vertical movement. Is appropriate.
[0027]
In the present embodiment, the means for fixing the object to be plated 1 is a means for fixing using the fixing rod 4. However, a clip is placed on the support column of the plating treatment basket 2, and the object to be plated 1 is formed by the clip. A means for fixing the periphery of the device may be used.
[0028]
As described above, according to the present embodiment, in the plating process, by applying an impact while the object to be plated 1 is fixed to the treatment basket 2, the non-through hole and the small-diameter through hole of the object to be plated 1 are applied. The staying reaction gas can be removed, and plating having a sufficient thickness can be performed.
[0029]
【The invention's effect】
As described above, according to the present invention, the reaction gas adhering to the object to be plated is surely released by applying an impact while the object to be plated such as a printed wiring board is fixed in the plating solution in the plating process. In addition, since it is possible to perform plating with a sufficient thickness, it is possible to obtain an effect that a printed wiring board or the like excellent in electrical connection reliability can be realized.
[Brief description of the drawings]
FIG. 1 is a perspective view of a plating apparatus according to an embodiment of the present invention. FIGS. 2A to 2C are cross-sectional views of an object to be plated immediately after immersion in a plating solution. FIG. c) Cross-sectional view of the object to be plated in the plating solution [Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 To-be-plated object 2 Processing basket 3 Plating tank 4 Fixing rod 5 Air cylinder 6 Basket receiver

Claims (1)

  A plating treatment basket in which an object to be plated having a non-through hole and a through hole having a hole diameter of 0.3 mm or less is fixed is immersed in a plating tank filled with a plating solution, and the plating treatment basket is shaken horizontally in the plating solution. A plating process method characterized by repeatedly performing an operation of impacting the object to be plated by lifting it upward while moving and allowing it to fall naturally in the vertical direction.

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